Cast: Adding helper crypto classes

media/cast/transport/transport_audio_sender.cc

Index: media/cast/transport/transport_audio_sender.cc
diff --git a/media/cast/transport/transport_audio_sender.cc b/media/cast/transport/transport_audio_sender.cc
index 1b451b0bc4103c58198afeeba35323a1d6a3b93d..e0a96110efe1b456a06044ef98abf8af6d381322 100644
--- a/media/cast/transport/transport_audio_sender.cc
+++ b/media/cast/transport/transport_audio_sender.cc
@@ -7,36 +7,19 @@
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
-#include "crypto/encryptor.h"
-#include "crypto/symmetric_key.h"
 #include "media/cast/transport/rtp_sender/rtp_sender.h"
 
 namespace media {
 namespace cast {
 namespace transport {
 
-// TODO(mikhal): Add a base class for encryption.
 TransportAudioSender::TransportAudioSender(
     const CastTransportConfig& config,
     base::TickClock* clock,
     PacedSender* const paced_packet_sender)
     : rtp_sender_(clock, config, true, paced_packet_sender),
-      initialized_(true) {
-  if (config.aes_iv_mask.size() == kAesKeySize &&
-      config.aes_key.size() == kAesKeySize) {
-    iv_mask_ = config.aes_iv_mask;
-    key_.reset(crypto::SymmetricKey::Import(
-        crypto::SymmetricKey::AES, config.aes_key));
-    encryptor_.reset(new crypto::Encryptor());
-    encryptor_->Init(key_.get(), crypto::Encryptor::CTR, std::string());
-  } else if (config.aes_iv_mask.size() != 0 ||
-             config.aes_key.size() != 0) {
-    initialized_ = false;
-    DCHECK_EQ(config.aes_iv_mask.size(), 0u)
-        << "Invalid Crypto configuration: aes_iv_mask.size" ;
-    DCHECK_EQ(config.aes_key.size(), 0u)
-        << "Invalid Crypto configuration: aes_key.size";
-  }
+      encryptor_() {
+  initialized_ = encryptor_.Initialize(config.aes_key, config.aes_iv_mask);
 }
 
 TransportAudioSender::~TransportAudioSender() {}
@@ -44,7 +27,7 @@ TransportAudioSender::~TransportAudioSender() {}
 void TransportAudioSender::InsertCodedAudioFrame(
     const EncodedAudioFrame* audio_frame,
     const base::TimeTicks& recorded_time) {
-  if (encryptor_) {
+  if (encryptor_.initialized()) {
     EncodedAudioFrame encrypted_frame;
     if (!EncryptAudioFrame(*audio_frame, &encrypted_frame)) {
       return;
@@ -58,14 +41,10 @@ void TransportAudioSender::InsertCodedAudioFrame(
 bool TransportAudioSender::EncryptAudioFrame(
     const EncodedAudioFrame& audio_frame,
     EncodedAudioFrame* encrypted_frame) {
-  if (!encryptor_->SetCounter(GetAesNonce(audio_frame.frame_id, iv_mask_))) {
-    NOTREACHED() << "Failed to set counter";
-    return false;
-  }
-  if (!encryptor_->Encrypt(audio_frame.data, &encrypted_frame->data)) {
-    NOTREACHED() << "Encrypt error";
+  if (!encryptor_.Encrypt(
+           audio_frame.frame_id, audio_frame.data, &encrypted_frame->data))
     return false;
-  }
+
   encrypted_frame->codec = audio_frame.codec;
   encrypted_frame->frame_id = audio_frame.frame_id;
   encrypted_frame->samples = audio_frame.samples;